1. Technical Field
The invention relates to a grid of synthetic material with two groups of parallel, load-bearing strands, wherein the strands of the first group extend in the longitudinal direction of the grid and the strands of the second group extend transversely to the longitudinal direction of the grid and the strands of both groups are joined together at their points of intersection.
2. Description of Related Art
Grids of this kind are known from numerous documents, inter alia from DE 20 00 937, DE 41 37 310, DE 41 38 506 and DE 199 15 722 A1.
The patent application DE 101 15 007, which has not yet been published, as well as the US patent application having the application Ser. No. 10/102,889, which is based on the priority of the latter application, describe a grid in which the spacing between the warp thread strands is greater in the edge regions extending in the warp direction than in the central region. This is a grid mat, in particular for reinforcing the ground and for securing or stabilising slopes and/or for reinforcing roadway coverings. The increased spacing of the warp thread strands in the edge regions facilitates the process of passing through threading elements which join the said mats together in their edge regions. The warp thread strands are of a greater width, which increases resistance to displacement, in the edge region.
A known grid for the mining sector is fastened as a tunnel protection grid to a roof or a side wall of a tunnel. In order to fasten the grid, steel cables are pulled at regular intervals through parallel courses into such grids, these being fasted to the roof or the wall. These steel cables are capable of bearing the necessary tensile forces. However the preparation of the grid in situ during installation by fixing the steel cables involves a lot of work.
It is desirable is to provide a grid which is easier to fasten than the known grids.